It is well known in the food packaging art to stuff synthetic or cellulosic tubular casings with various meat products. These products are typically processed and introduced into the casings in the form of an emulsion or comminuted form.
In automated processes, processed meat products are typically introduced into a shirred casing. This is a casing which is shirred to a much shorter length than the actual length of the casing. As the automated process is operated, the shirred casing is fed typically over a sizing ring which unshirres the casing before stuffing with the meat product. Of course, the diameter of the sizing ring will be predetermined in accordance with the size of the intended casing which will be used for the particular packaging operation.
In using a standard sizing ring for a food casing, tensioning of the casing to avoid air voids and maintain stuff diameter is difficult. Casing dimensions can vary, requiring the substitution of another, "better fitting" ring.
It is also common practice to introduce liquid smoke, colorant, or other similar additives to certain processed meat products such as sausage or luncheon meats to impart the desired flavor or color to the food product. These additives are usually blended into the food product before the stuffing operation, or impregnated into the casing material itself if the composition of the casing permits impregnation of such additives.
This common practice requires an additional step prior to the stuffing operation. In the case of pre-blending the colorant or liquid smoke into the food product, sometimes more additive is used than is really required. For example, if only the surface of the food product requires the colorant or liquid smoke, pre-blending uses excess additive which is blended throughout the food product.
Additionally, in the case of some synthetic casings, liquid smoke and colorant are not easily added to the casing material itself, and if added are not readily retained by the casing material.
For these reasons, it is desirable to provide a method and apparatus for coating the exterior of a processed meat product, packaged in a casing, which does not require the pre-blending of the additive before the stuffing operation, or impregnation of the casing material itself with the additive.
U.S. Pat. No. 4,958,412 (Stanek) discloses a sizing ring in which a channel located within a cylindrical sleeve portion allows for the transfer of a liquid additive to the outer extremity of the sizing ring. Grooves in the outer face of the ring transmit the additive from the ring onto the interior of the casing as it is unshirred. The liquid additive is then transferred to the exterior surface of the stuffed meat or other product.
Using the color ring described in U.S. Pat. No. 4,958,412 to deposit color or liquid smoke on the interior surface of a shirred casing makes certain demands on the packaging system. In addition to the considerations for standard rings, some standard tensioning devices, located downstream of the sizing ring on the front end discharge of the stuffing horn, can undesirably wick away the color deposited at the ring.
It is an object of the present invention to offer a solution to the problems of casing size variation, and color removal in the case of color rings.